mirror of
https://github.com/storytold/pdfcraft.git
synced 2026-10-27 11:37:59 -06:00
A Line annotation without an appearance was drawn along /L with its endings there, ignoring /LL, /LLE, /LLO, /Cap, /CP and /CO. With /LL, /L gives the ends of the leader lines, not of the line itself. - The line sits |LL| + LLO from /L, on the left of travel for a positive /LL; leader lines run from LLO off /L to LLE past the line. - /LE endings are drawn at the line itself. - /Cap true draws /Contents (or the plain text of /RC) in black Helvetica 10, turned with the line: Inline breaks the stroke around it, Top sets it above, /CO shifts it (with a tick when moved off). - PdfCraft measurements keep /PCMeasureValue as their caption. - undrawable_text reports caption text the standard font can't draw. - Non-finite, huge and negative values, and a zero-length /L, are handled leniently; captions are cut to 256 characters. Claude-Session: https://claude.ai/code/session_0175FWj4xFhMhSH3UpMU8DSC Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
66 lines
4.0 KiB
Markdown
66 lines
4.0 KiB
Markdown
# pdfcraft-annot
|
||
|
||
Comments (annotations), ISO 32000-2 §12.5. Layer L3, depends on `pdfcraft-cos`, `pdfcraft-fonts` and `pdfcraft-model`.
|
||
|
||
## What it does
|
||
|
||
- **Builders** for the comment types Acrobat's commenting tools create: sticky note (`Text` +
|
||
`Popup`), highlight, underline, strikethrough, squiggly, rectangle (`Square`), oval (`Circle`),
|
||
line and arrow (`Line` with `/LE`), freehand drawing (`Ink`) and text box (`FreeText`).
|
||
- **Appearance streams** (`appearance::build`) generated from the annotation dictionary, so new
|
||
and restyled comments look the same in every viewer. Highlights multiply (`/BM /Multiply`).
|
||
A line's leader lines (`/LL`, `/LLE`, `/LLO`) and caption (`/Cap`, `/CP`, `/CO`) are drawn as
|
||
ISO 32000-2 Table 178 places them, the caption in black Helvetica 10.
|
||
Note icons are PdfCraft's own drawings. Text boxes use standard Helvetica (WinAnsi), with
|
||
line breaking by approximate Helvetica proportions (no font program is bundled). Text it can't
|
||
draw (in a text box, callout, Fill & Sign text, line caption, measurement label or dynamic
|
||
stamp's by-line; `appearance::undrawable_text`) is kept as typed and drawn as `?`, and the comment is marked with
|
||
the first such character (`pdfcraft_fonts::UNDRAWN_MARK`) so the engine reports the edit and
|
||
flattening refuses to make it permanent. Two refusals (`AnnotError::Undrawable`): a redaction
|
||
mark's overlay text, which becomes page content when applied; and a restyle or resize of a
|
||
comment another program drew with a font that has those characters, whose appearance is kept
|
||
rather than redrawn with `?` (new text for it is taken).
|
||
- **Edits:** reply (`/IRT`), set review status (a `/State` reply, as Acrobat's "Set status"
|
||
does), change text, move, resize, restyle, delete (with pop-up and replies).
|
||
|
||
## API sketch
|
||
|
||
```rust
|
||
let index = add_annotation(&mut doc, &NewAnnotation { page, shape, style, contents, author }, &meta)?;
|
||
add_reply(&mut doc, page, index, "Agreed", "Ada", &meta)?;
|
||
set_review_state(&mut doc, page, index, ReviewState::Accepted, "Ada", &meta)?;
|
||
move_annotation(&mut doc, page, index, dx, dy, &meta)?;
|
||
set_style(&mut doc, page, index, Some(rgb), Some(0.5), Some(2.0), &meta)?;
|
||
delete_annotation(&mut doc, page, index)?;
|
||
signature_image(&doc, page, index)?; // embedded image XObject of Fill & Sign signature/initials
|
||
```
|
||
|
||
A comment is addressed by `(page, index in /Annots)`, the same pair
|
||
`pdfcraft_render::Annotation` reports. `Meta` carries the date and the `/NM` id so edits stay
|
||
deterministic; the engine supplies them.
|
||
|
||
## Fidelity rules
|
||
|
||
- Unknown keys are kept. Inline annotation dictionaries are promoted to indirect objects only
|
||
when an edit needs a reference to them.
|
||
- `set_style` refuses (and changes nothing) when it cannot redraw the comment, e.g. stamps,
|
||
cloudy borders or callouts, instead of leaving a stale appearance.
|
||
- Replies get the parent's `/Rect` and an empty appearance: they appear in comment lists but
|
||
never paint a second icon.
|
||
- Resizing a stamp changes its `/Rect` and preserves its original appearance and resources;
|
||
viewers scale that appearance into the new rectangle. Locked stamps refuse the edit.
|
||
- Picture stamps (a natural-size or explicit-rectangle image, a PDF page, or an image
|
||
signature) and PdfCraft's rubber stamps counterrotate their appearance on rotated pages, so
|
||
the picture or label reads upright as the page is displayed. Restyling a picture stamp keeps
|
||
that appearance matrix. The rotation is the page's `/Rotate` at placement.
|
||
- Sticky notes and file attachments are not counterrotated: they carry the NoRotate flag and
|
||
their icon is drawn in an unturned 20 × 20 box. A viewer keeps them upright on a turned page,
|
||
about the upper-left corner of `/Rect` (ISO 32000-2 §12.5.3). PdfCraft's renderer does so
|
||
(vendored hayro-interpret patch 37), and `Summary::no_rotate` tells the UI where the icon is
|
||
drawn.
|
||
|
||
## Not yet
|
||
|
||
Callouts, polygons and polylines, clouds, carets (insert/replace text), stamps, file
|
||
attachments, rich text (`/RC`, `/DS`), and the shared named-appearance cache Acrobat writes.
|